Hib (Haemophilus Influenzae Type B) vaccine

  • A conjugate vaccine (made from a tiny fragment of the bacteria's sugar-coat attached to a protein) against Hib was introduced in the UK and Ireland in 1992, and provides long-lasting immunity. 
  • Since the introduction of the Hib vaccine, the incidence of meningitis cause by Haemophilus influenzae has been reduced by over 90%, across the UK and Ireland 1,2 .
  • Introduction of the conjugate Hib vaccine has also reduced carriage rates of the bacteria .
  • Before the vaccine was introduced, a large proportion of children under age 5 carried the bacteria. Now that vaccination is routine, carriage of the bacteria is much less common, and as a result protection is extended to the rest of the population, even those not immunised. This is called 'herd immunity'.

Is Hib vaccine safe?

Millions of doses given to children worldwide over more than a decade have established an excellent safety record. Adverse reactions are no more common than for other vaccines routinely given to babies and children. The Hib vaccine is not a live vaccine and cannot cause even a very mild form of the disease.

Who gets Hib vaccine?

Currently in the UK, the vaccine is offered to babies at 2, 3, and 4 months of age in the routine immunisation programme, with a Hib booster (given as combined Hib/MenC) offered at 12-13  months of age. 

In addition, in the UK, Hib vaccine is recommended for older children and adults with certain immune deficiencies such as people with HIV or those without a functioning spleen (asplenics and hyposplenics), including people who have sickle cell disorder 4 .

Currently in Ireland, the vaccine is offered to babies at 2, 4 and 6 months of age in the routine immunisation programme, with a Hib booster dose offered at 12 months of age.

In addition to babies, in Ireland, Hib vaccine is recommended for all children under four years of age who have not previously had the vaccine and for anyone with malfunctioning or lack of spleen, sickle cell disease, HIV or other immunodeficiency, irrespective of how old they are 5 .

Is Hib still an important cause of meningitis?

The Hib vaccine is very effective, but no vaccine is 100% effective. It does not work as well in children with certain immune problems. In addition, a very small proportion of perfectly healthy children do not respond to the vaccine well enough to be protected against Hib meningitis. It is unusual for adults and older children to be susceptible to Hib infection, but cases are known to occur, particularly in hospitalised, sick and elderly patients. Illness caused by non-b types of Haemophilus influenzae is also being monitored.

Immunisation has dramatically reduced cases of Hib meningitis, but in countries which have not introduced the vaccine, Hib is still a major cause of serious disease in children.


References

  1. JCVI Statement: Haemophilus influenzae type b (Hib) Disease and Hib Vaccine. Executive Summary. http://www.advisorybodies.doh.gov.uk/jcvi/hib.pdf (accessed 17 May 2007).
  2. Health Protection Surveillance Centre. Hib FAQs, How safe and effective is the Hib vaccine? http://www.immunisation.ie/en/HealthcareProfessionals/Hib/#howsafe (accessed May 2007).
  3. Frasch CE, Haemophilus influenzae Type b Conjugate and Combination Vaccines. 1995. Clin.Immunother. 4 (5):376-386
  4. Department of Health. Immunisation against infectious diseases. Chapter 16: Haemophilus influenzae type B (Hib) pages 127-135. Ed Salisbury D, Ramsay M and Noakes K. 2006. Third edition. TSO. http://www.dh.gov.uk/en/Policyandguidance/Healthandsocialcaretopics/Greenbook/DH_4097254 (accessed 17 May 2007).
  5. Immunisation Guidelines 2002.
    http://www.ndsc.ie/hpsc/A-Z/VaccinePreventable/Vaccination/Guidance/ (accessed May 2007)
  6. Professional Letter-  Chief Medical Officer (2003)2: Planned HIB vaccination catch-up campaign: further information Department of Health. http://www.dh.gov.uk/en/Publicationsandstatistics/Lettersandcirculars/Professionalletters/Chiefmedicalofficerletters/DH_4004833 (accessed 17 May 2007)